Resist pattern, process for producing same, and utilization thereof

ABSTRACT

A resist pattern having a film thickness of 1 to 100 μm and an aspect ratio (ratio of the line width to the film thickness of the resist pattern) of 3.5 or higher is provided in accordance with the present invention, the resist pattern being useful for increasing the density of a semiconductor package substrate circuit, and use of the resist pattern enabling a low conductor resistance to be maintained in fine wiring.  
     This resist pattern can be produced using, for example, a photosensitive resin composition that includes (A) a binder polymer, (B1) a photopolymerizable compound having three ethylenically unsaturated bonds per molecule, (C) a photopolymerization initiator, and (D) either or both of a compound represented by general formula (I):  
                 
 
     (in the formula, m is an integer of 2 to 6)  
     or a compound represented by general formula (II).

TECHNICAL FIELD

[0001] The present invention relates to a resist pattern, aphotosensitive resin composition, a photosensitive element using this, aprocess for producing the resist pattern, and a process for producing asemiconductor package substrate.

BACKGROUND ART

[0002] Conventionally, in the field of printed wiring board production,semiconductor package substrate production, etc., with regard to resistmaterials used in etching, plating, etc., a photosensitive resincomposition and a photosensitive element obtained from thephotosensitive resin composition, a support, and a protective film arewidely used. That is, after lamination of a photosensitive element totop of a copper substrate and pattern exposure, the cured portion isremoved by a developing solution, the pattern is formed by etching(subtractive process) or plating (additive process), and the curedportion is then stripped off the substrate to give a wiring board orsubstrate.

[0003] Accompanying the miniaturization and increased functionality ofelectronic equipment in recent years, there has been a demand for anincrease in the wiring line/space (L/S) density. There is also a desire,from the viewpoint of improving the workability, for a photosensitiveresin composition that has high sensitivity and low plating bathcontamination.

[0004] High sensitivity photopolymerization initiators are disclosed inGerman Patent No. 2,027,467, EP-A-11,786, EP-A-220, EP-A-589,JP-A-6-69631, etc. Furthermore, U.S. Pat. No. 3,479,185 discloses aphotosensitive resin composition in which high sensitivity is achievedby a combination of a hydrogen-donating compound and a2,4,5-triarylimidazole dimer, which is a photopolymerization initiatorthat gives little plating bath contamination.

[0005] However, the high sensitivity photopolymerization initiatorsdisclosed in the above-mentioned specifications have the problem ofplating bath contamination, and the case in which the2,4,5-triarylimidazole dimer is used has the problem that if the amountthereof used is increased in order to adjust to a required sensitivity,then the resist line width increases, and if the amount of hydrogen-donating compound is increased, then the adhesion to copper and thestorage stability deteriorate.

DISCLOSURE OF INVENTION

[0006] Currently, the line/space (L/S) density of wiring has increasedto approximately 50 to 100 μm, and it can be expected that, inparticular, substrates of semiconductor package such as BGA and CSP willbe required to have a line/space (L/S) of 30 μm or less. Such a demandfor higher density is expected to further increase in the future.

[0007] On the other hand, as the density of copper wiring increases, thewiring distance can be expected to be shorten, but since the increase infineness of the wiring can be expected to be even more marked, theelectrical resistance (conductor resistance) of the wiring increases,and an adverse effect on signal propagation, called RC delay, can beexpected to occur. This conductor resistance is represented by formula(1) below:

R=ρL/A  (1)

[0008] (in the formula, R represents the conductor resistance, ρrepresents the conductor resistivity, L represents the conductor length,and A represents the conductor cross section.)

[0009] It can therefore be expected that in fine wiring it will benecessary to increase the copper thickness so as to increase the crosssection in order to maintain a low conductor resistance. For example,when the pattern width is 6 μm, in order to obtain the same crosssection as that of a copper wiring pattern having a pattern width of 10μm and a copper thickness of 15 μm, it is necessary for the copperthickness to be 25 μm.

[0010] Taking the above points into consideration, in order to satisfythe requirement for higher density by increasing the resolution of aresist used in processing a package substrate, it is important toconsider not only the line/space (L/S) value but also the ratio of theline width to the film thickness of the resist pattern, namely, theaspect ratio.

[0011] Moreover, taking into consideration the workability during resiststripping after plating, the required film thickness of the resistpattern is generally 1.2 times the thickness of copper plating, and itis therefore necessary for the film thickness of the resist to be 30 μmfor a copper wiring pattern width of 6 μm. In this case, the aspectratio of the resist pattern is required to be 5.0.

[0012] The aspect ratio referred to here is the ratio of the line widthto the film thickness of the resist, that is, it can be represented byformula (2) below.

Aspect ratio=Film thickness of resist pattern (μm)/line width of resistpattern (μm)  (2)

[0013] As hereinbefore described, there is a desire for a photosensitiveresin composition and a photosensitive element that can produce a resistpattern having a high aspect ratio, but this desire can not be satisfiedby the conventional techniques since, if the adhesion of resist finelines to a substrate is enhanced, the line width increases therebydegrading resolution, it is difficult to increase the contrast betweenan exposed area and an unexposed area so as to obtain an adequate aspectratio and, furthermore, there is a tendency for the resist pattern tocollapse due to the spray pressure of a developing solution, etc. duringdevelopment.

[0014] It is therefore an object of the present invention to provide ahigh resolution resist pattern that is useful for increasing the densityof a semiconductor package substrate circuit, use of the resist patternenabling a low conductor resistance to be maintained in fine wiring(that is, in order to maintain a low conductor resistance in finewiring, the copper film thickness can be increased so as to increase itscross section).

[0015] It is another object of the present invention to provide aphotosensitive resin composition that can produce a resist pattern or agroup of resist patterns which have high resolution and which are usefulfor increasing the density of a semiconductor package substrate circuit,use of the resist pattern enabling a low conductor resistance to bemaintained in fine wiring.

[0016] It is yet another object of the present invention to provide aphotosensitive resin composition that can provide a resist patternhaving high resolution and a high aspect ratio, the photosensitive resincomposition having excellent sensitivity, resolution, resistance toscumming, and plating resistance, and being useful for increasing thedensity of a semiconductor package substrate circuit.

[0017] It is a further object of the present invention to provide aphotosensitive element that can provide a resist pattern having highresolution and a high aspect ratio, the photosensitive element havingexcellent sensitivity, resolution, resistance to scumming, and platingresistance, and being useful for increasing the density of asemiconductor package substrate circuit.

[0018] It is a still further object of the present invention to providea process for producing a resist pattern, the process being capable ofproducing a high resolution resist pattern with good productivity andworkability, and the resist pattern enabling a low conductor resistanceto be maintained in fine wiring and being useful for increasing thedensity of a semiconductor package substrate circuit.

[0019] It is yet another object of the present invention to provide aprocess for producing a semiconductor package substrate that is usefulfor increasing the density of a semiconductor package substrate circuit,the process enabling fine wiring with the conductor resistancemaintained low to be carried out with good workability and productivity.

[0020] A first aspect of the present invention provides a resist patternhaving a film thickness of 1 to 100 μm and an aspect ratio (ratio of theline width to the film thickness of the resist pattern) of 3.5 orhigher.

[0021] A second aspect of the present invention provides aphotosensitive resin composition that can produce a resist patternhaving a film thickness of 1 to 100 μm and an aspect ratio (ratio of theline width to the film thickness of the resist pattern) of 3.5 orhigher.

[0022] A third aspect of the present invention provides a photosensitiveresin composition that can produce a group of resist patterns in which aresist pattern having a film thickness of 1 to 100 μm and an aspectratio (ratio of the line width to the film thickness of the resistpattern) of 3.5 or higher is adjacent, via a space having the same widthas the line width of the resist pattern, to a resist pattern having afilm thickness of 1 to 100 μm and an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higher.

[0023] A fourth aspect of the present invention provides aphotosensitive resin composition that includes (A) a binder polymer,(B1) a photopolymerizable compound having three ethylenicallyunsaturated bonds per molecule, (C) a photopolymerization initiator, and(D) either or both of a compound represented by general formula (I):

[0024] (in the formula, m is an integer of 2 to 6)

[0025] or a compound represented by general formula (II).

[0026] A fifth aspect of the present invention provides a photosensitiveresin composition that includes (A) a binder polymer, (B) aphotopolymerizable compound having at least one ethylenicallyunsaturated bond per molecule, (C) a photopolymerization initiator, and(E) a leuco dye, the amount of component (E) added being 0.3 to 0.6parts by weight relative to 100 parts by weight of the total ofcomponent (A) and component (B).

[0027] A sixth aspect of the present invention provides a photosensitiveresin composition that includes (A) a binder polymer, (B) aphotopolymerizable compound having at least one ethylenicallyunsaturated bond per molecule, and (C) a photopolymerization initiator,the component (C) including an N,N′-tetraalkyl-4,4′-diaminobenzophenoneat 0.04 to 0.08 parts by weight relative to 100 parts by weight of thetotal of component (A) and component (B).

[0028] A seventh aspect of the present invention provides aphotosensitive element that is obtained by forming on a support a resistlayer formed from the photosensitive resin composition according to theabove-mentioned present invention.

[0029] An eighth aspect of the present invention provides a process forproducing a resist pattern having an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higherusing the photosensitive resin composition according to the presentinvention, the process including the following steps:

[0030] i) a step of forming on a substrate at a dry film thickness of 1to 100 μm a resist layer formed from the photosensitive resincomposition according to the present invention;

[0031] ii) a step of imagewise exposing the resist layer to actinicradiation so that an exposed area thereof is light cured; and

[0032] iii) a step of selectively removing an unexposed area of theresist layer by development.

[0033] A ninth aspect of the present invention provides a process forproducing a resist pattern having an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higher, theprocess including the following steps:

[0034] i) a step of forming on a substrate at a dry film thickness of 1to 100 μm a resist layer formed from a photosensitive resin composition,the resist layer having an absorbance of 0.50 or less at an actinicradiation wavelength of 365 nm;

[0035] ii) a step of imagewise exposing the resist layer to actinicradiation so that an exposed area thereof is light cured; and

[0036] iii) a step of selectively removing an unexposed area of theresist layer by development.

[0037] A tenth aspect of the present invention provides a process forproducing a resist pattern having an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higher, theprocess including the following steps:

[0038] i) a step of forming on a substrate at a dry film thickness of 1to 100 μm a resist layer formed from a photosensitive resin composition;

[0039] ii) a step of imagewise exposing the resist layer to actinicradiation through a glass negative pattern so that an exposed areathereof is light cured; and

[0040] iii) a step of selectively removing an unexposed area of theresist layer by development.

[0041] An eleventh aspect of the present invention provides a processfor producing a resist pattern having an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higher, theprocess including the following steps:

[0042] i) a step of forming on a substrate at a dry film thickness of 1to 100 μm a resist layer formed from a photosensitive resin composition;

[0043] ii) a step of imagewise exposing the resist layer to a collimatedlight beam so that an exposed area thereof is light cured; and

[0044] iii) a step of selectively removing an unexposed area of theresist layer by development.

[0045] A twelfth aspect of the present invention provides a process forproducing a resist pattern having an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higherusing the photosensitive element according to the present invention, theprocess including the following steps:

[0046] i) a step of laminating to a substrate the photosensitive elementaccording to the present invention, the photosensitive element beingobtained by forming on a support a resist layer formed from thephotosensitive resin composition according to the present invention, insuch a manner that the resist layer is bonded to a surface of thesubstrate;

[0047] ii) a step of imagewise exposing the resist layer to actinicradiation so that an exposed area thereof is light cured; and

[0048] iii) a step of selectively removing an unexposed area of theresist layer by development.

[0049] A thirteenth aspect of the present invention provides a processfor producing a semiconductor package substrate wherein a circuit isformed by subjecting to an additive process a substrate on which theresist pattern according to the present invention has been produced.

[0050] A fourteenth aspect of the present invention provides a processfor producing a semiconductor package substrate wherein a circuit isformed by subjecting to an additive process a substrate on which aresist pattern has been produced by the process for producing a resistpattern according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051]FIG. 1 is a schematic drawing showing an embodiment of thephotosensitive element according to the present invention.

[0052]FIG. 2 is a schematic drawing showing an example of steps of theprocess for producing the resist pattern according to the presentinvention.

[0053]FIG. 3 is a schematic drawing showing an example of steps forproducing the semiconductor package substrate according to the presentinvention by a full additive process.

[0054]FIG. 4 is a schematic drawing showing an example of steps forproducing the semiconductor package substrate according to the presentinvention by a semi additive process.

[0055]FIG. 5 is a schematic drawing showing an example of steps forproducing the semiconductor package substrate according to the presentinvention by a panel additive process.

[0056]FIG. 6 shows SEM photographs of a magnified part of a resistpattern obtained in an experimental example of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0057] A mode for carrying out the present invention is explained indetail below. In the present invention a (meth)acrylic acid denotes anacrylic acid and the corresponding methacrylic acid, a (meth)acrylatedenotes an acrylate and the corresponding methacrylate, and a(meth)acryloyl group denotes an acryloyl group and the correspondingmethacryloyl group.

[0058] The resist pattern according to the present invention has a filmthickness of 1 to 100 μm and an aspect ratio (ratio of the line width tothe film thickness of the resist pattern) of 3.5 or higher. Satisfyingthese requirements can provide a high resolution resist pattern in whicha low conductor resistance is maintained for fine wiring, and which isuseful for increasing the density of a semiconductor package substratecircuit.

[0059] With regard to techniques for producing such a resist pattern,for example, there are methods a to h below, and carrying out methods ato h singly or in an appropriate combination of a plurality thereof canproduce such a resist pattern.

[0060] Method a: as a resist material, a photosensitive resincomposition is used that is capable of producing a resist pattern havinga film thickness of 1 to 100 μm and an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higher.

[0061] Method b: as a resist material, a photosensitive resincomposition is used that is capable of producing a group of resistpatterns in which a resist pattern having a film thickness of 1 to 100μm and an aspect ratio (ratio of the line width to the film thickness ofthe resist pattern) of 3.5 or higher is adjacent, via a space having thesame width as the line width of the resist pattern, to a resist patternhaving a film thickness of 1 to 100 μm and an aspect ratio (ratio of theline width to the film thickness of the resist pattern) of 3.5 orhigher.

[0062] Method c: as a resist material, a photosensitive resincomposition is used that includes (A) a binder polymer, (B1) aphotopolymerizable compound having three ethylenically unsaturated bondsper molecule, (C) a photopolymerization initiator, and (D) either orboth of a compound represented by general formula (I):

[0063] (in the formula, m is an integer of 2 to 6)

[0064] or a compound represented by formula (II).

[0065] Method d: as a resist material, a photosensitive resincomposition is used that includes (A) a binder polymer, (B) aphotopolymerizable compound having at least one ethylenicallyunsaturated bond per molecule, (C) a photopolymerization initiator, and(E) a leuco dye, the amount of the component (E) added being 0.3 to 0.6parts by weight relative to 100 parts by weight of the total ofcomponent (A) and component (B).

[0066] Method e: as a resist material, a photosensitive resincomposition is used that includes (A) a binder polymer, (B) aphotopolymerizable compound having at least one ethylenicallyunsaturated bond per molecule, and (C) a photopolymerization initiator,an N,N′-tetraalkyl-4,4′-diaminobenzophenone being included as thecomponent (C) at 0.04 to 0.08 parts by weight relative to 100 parts byweight of the total of component (A) and component (B).

[0067] Method f: as a resist material, a photosensitive resincomposition is used that can form a resist layer having an absorbance of0.50 or less at an actinic radiation wavelength of 365 nm, this isapplied as a layer on a substrate at a dry film thickness of 1 to 100 μmto give a resist layer, the resist layer is imagewise exposed to actinicradiation so that an exposed area thereof is light cured, and anunexposed area of the resist layer is removed by development.

[0068] Method g: a resist layer formed from a photosensitive resincomposition is formed on a substrate at a dry film thickness of 1 to 100μm, the resist layer is imagewise exposed to actinic radiation through aglass negative pattern so that an exposed area thereof is light cured,and an unexposed area of the resist layer is removed by development.

[0069] Method h: a resist layer formed from a photosensitive resincomposition is formed on a substrate at a dry film thickness of 1 to 100μm, the resist layer is imagewise exposed to a collimated light beam sothat an exposed area thereof is light cured, and an unexposed area ofthe resist layer is removed by development.

[0070] In the above-mentioned methods a and b, it is preferable toinclude, as specific components, (B1) the photopolymerizable compoundhaving three ethylenically unsaturated bonds per molecule and either oneor both of (D) the compound represented by general formula (I) above orthe compound represented by formula (II) above.

[0071] In the above-mentioned methods c, d, and e, it is preferable tofurther include at least one type of compound from (B2) a2,2-bis(4-((meth)acryloxypolyalkoxy)phenyl) propane, (B3) a polyalkyleneglycol di(meth)acrylate, and (B4) a compound having at least oneethylenically unsaturated bond and at least one phenyl or phenylenegroup per molecule. Furthermore, it is preferable to include a2,4,5-triarylimidazole dimer as the photopolymerization initiator (C).Moreover, in the methods d and e, it is preferable to include thecomponent (B1) above as the component (B).

[0072] Each of the components of the photosensitive resin compositionthat is preferably used for forming the resist pattern according to thepresent invention is explained below.

[0073] Examples of the binder polymer (A) include an acrylic resin, astyrene resin, an epoxy resin, an amide resin, an amide epoxy resin, analkyd resin, and a phenol resin. From the viewpoint of the alkalinedevelopment properties, the acrylic resin is preferable.

[0074] It is also possible to use as the component (A) a product ofradical polymerization of a polymerizable monomer. Examples of thepolymerizable monomer include styrene, polymerizable styrene derivativessuch as vinyltoluene, α-methylstyrene, p-methylstyrene, andp-ethylstyrene, acrylamide, acrylonitrile, an ester of a vinylalcoholsuch as vinyl n-butyl ether, an alkyl (meth)acrylate ester,tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate,diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate,2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl(meth)acrylate, (meth)acrylic acid, α-bromo(meth)acrylic acid,α-chloro(meth)acrylic acid, β-furyl(meth)acrylic acid,β-styryl(meth)acrylic acid, maleic acid, maleic anhydride, monoesters ofmaleic acid such as monomethyl maleate, monoethyl maleate, andmonoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamicacid, itaconic acid, crotonic acid, and propiolic acid. They can be usedsingly or in a combination of two or more types.

[0075] Examples of the alkyl (meth)acrylate ester include methyl(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl(meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl(meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, andstructural isomers thereof. They can be used singly or in a combinationof two or more types.

[0076] From the viewpoint of the alkaline development properties, it ispreferable for the component (A) to have a carboxyl group, and thecomponent (A) can be produced by, for example, radical polymerization ofa polymerizable monomer having a carboxyl group and anotherpolymerizable monomer. With regard to the polymerizable monomer having acarboxyl group, methacrylic acid is preferable. Furthermore, from theviewpoint of flexibility, the component (A) preferably includes styreneor a styrene derivative as a polymerizable monomer. In order to maintainboth good adhesion and good stripping properties while including styreneor a styrene derivative as a comonomer component, the proportion ofstyrene or styrene derivative in the copolymer is preferably at least 3wt % from the viewpoint of the adhesion, preferably at most 30 wt % fromthe viewpoint of the size of stripped pieces and the stripping time,more preferably 4 to 28 wt %, and particularly preferably 5 to 27 wt %.

[0077] The acid value of the component (A) is preferably at least 30 mgKOH/g from the viewpoint of development time, preferably at most 200 mgKOH/g from the viewpoint of resistance to the developing solution of alight cured resist, and more preferably 50 to 150 mg KOH/g.

[0078] The weight-average molecular weight of the component (A)(measured by gel permeation chromatography (GPC) and converted by meansof a calibration curve prepared using a polystyrene standard) ispreferably at least 20,000 from the viewpoint of the resistance to thedeveloping solution, preferably at most 300,000 from the viewpoint ofthe development time, and more preferably 30,000 to 150,000.

[0079] These binder polymers are used singly or in a combination of twoor more types. Examples of the combination of two or more types ofbinder polymers include a combination of two or more binder polymers oftypes that are different from each other, a combination of two or moretypes of binder polymers formed from different comonomers, a combinationof two or more types of binder polymers having different weight-averagemolecular weights, and a combination of two or more types of binderpolymers having different dispersities. It is also possible to use apolymer having a multimodal molecular weight distribution disclosed inJP-A-11-327137. These binder polymers may have a photosensitive group asnecessary.

[0080] With regard to the photopolymerizable compound (B) having atleast one ethylenically unsaturated bond per molecule, for example, aradically polymerizable compound can be preferably used. Theethylenically unsaturated bond referred to here denotes a polymerizableethylenically unsaturated bond. Specific examples include a compoundobtained by reacting a polyhydric alcohol with an α,β-unsaturatedcarboxylic acid, various types of bisphenol A (meth)acrylate compound,which will be described later as component (B2), a compound obtained byreacting a compound having a glycidyl group with an α,β-unsaturatedcarboxylic acid, a urethane monomer such as a (meth)acrylate compoundhaving a urethane bond in the molecule, various types ofnonylphenoxypolyethyleneoxy (meth)acrylate, which will be describedlater as component (B4), phthalic acid compounds such asγ-chloro-β-hydroxypropyl-β′-(meth)acryloyloxyethyl o-phthalate and aβ-hydroxyalkyl-β′-(meth)acryloyloxyalkyl o-phthalate, and alkyl(meth)acrylate esters. They can be used singly or in a combination oftwo or more types.

[0081] Examples of the compound obtained by reacting a polyhydricalcohol with an α,β-unsaturated carboxylic acid include various types ofpolyalkylene glycol di(meth)acrylate, which will be described later ascomponent (B3), trimethylolpropane di(meth)acrylate, various types oftri(meth)acrylate compound, which will be described later as component(B1), tetramethylolmethane tetra(meth)acrylate, dipentaerythritolpenta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0082] Examples of the (meth)acrylate compound having a urethane bond inthe molecule include an adduct of a (meth)acrylic monomer having an OHgroup in a β-position with a diisocyanate compound such as isophoronediisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, or1,6-hexamethylene diisocyanate, tris((meth)acryloxytetraethylene glycolisocyanate)hexamethylene isocyanurate, an EO-modified urethanedi(meth)acrylate, and an EO- and PO-modified urethane di(meth)acrylate.Examples of the EO-modified urethane di(meth)acrylate include UA-11(product name, manufactured by Shin-Nakamura Chemical Co., Ltd.)Examples of the EO- and PO-modified urethane di(meth)acrylate includeUA-13 (product name, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0083] In a preferred embodiment, the photopolymerizable compound (B1)having three ethylenically unsaturated bonds per molecule can be used asthe component (B). By including the component (B1) the resistcross-linking density can be improved, which is effective in preventingcollapse of the resist pattern.

[0084] The component (B1) is not particularly limited as long as it hasthree ethylenically unsaturated bonds per molecule, and examples thereofinclude trimethylolpropane tri(meth)acrylate, an EO-modifiedtrimethylolpropane tri(meth)acrylate, a PO-modified trimethylolpropanetri(meth)acrylate, an EO- and PO-modified trimethylolpropanetri(meth)acrylate, pentaerythritol tri(meth)acrylate, an EO-modifiedpentaerythritol tri(meth)acrylate, a PO-modified pentaerythritoltri(meth)acrylate, an EO- and PO-modified pentaerythritoltri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, anEO-modified tetramethylolmethane tri(meth)acrylate, a PO-modifiedtetramethylolmethane tri(meth)acrylate, and an EO- and PO-modifiedtetramethylolmethane tri(meth)acrylate. Available examples thereofinclude A-TTM-3 (trade name, tetramethylolmethane triacrylatemanufactured by Shin-Nakamura Chemical Co., Ltd.) and TMPT21E andTMPT30E (sample names, EO-modified trimethylolpropane trimethacrylate,produced by Hitachi Chemical Co., Ltd.) They can be used singly or in acombination of two or more types. The EO above denotes ethylene oxide,and an EO-modified compound has an ethylene oxide block structure. ThePO above denotes propylene oxide, and a PO-modified compound has apropylene oxide block structure.

[0085] In another preferred embodiment, the2,2-bis(4-((meth)acryloxypolyalkoxy)phenyl)propane (B2) can be used inorder to further improve the resolution, the resistance to scumming, andthe plating resistance. Examples of the component (B2) include a2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, a2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, a2,2-bis(4-((meth)acryloxypolybutoxy)phenyl)propane, and a2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl) propane. Theplurality of alkoxy groups in the component (B2) may be identical toeach other or different from each other. When two or more types ofalkoxy groups are present, the two or more types of alkoxy groups may bepresent randomly or as blocks. Examples of such a compound having two ormore types of alkoxy groups include the2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl) propane. Thesecomponents (B2) can be used singly or in a combination of two or moretypes.

[0086] Examples of the 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane include those having 2 to 16 ethoxy groups; specificexamples thereof include2,2-bis(4-((meth)acryloxydiethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxytriethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxytetraethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxypentaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxyhexaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxyheptaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxyoctaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxynonaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxydecaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxyundecaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxydodecaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxytridecaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxytetradecaethoxy)phenyl)propane,2,2-bis(4-((meth)acryloxypentadecaethoxy)phenyl)propane, and2,2-bis(4-((meth)acryloxyhexadecaethoxy)phenyl)propane.2,2-Bis(4-(methacryloxypentaethoxy)phenyl)propane is commerciallyavailable as BPE-500 (trade name, manufactured by Shin-Nakamura ChemicalCo., Ltd.) and 2,2-bis(4-(methacryloxypentadecaethoxy)phenyl)propane iscommercially available as BPE-1300 (trade name, manufactured byShin-Nakamura Chemical Co., Ltd.). They can be used singly or in acombination of two or more types.

[0087] Examples of the2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl) propane include2,2-bis(4-((meth)acryloxydiethoxyoctapropoxy)phenyl) propane,2,2-bis(4-((meth)acryloxytetraethoxytetrapropoxy) phenyl)propane, and2,2-bis(4-((meth)acryloxyhexaethoxyhexapropoxy)phenyl) propane. They canbe used singly or in a combination of two or more types.

[0088] In another preferred embodiment, in order to further improvevarious resist properties such as the resolution, the resistance toscumming, and the plating resistance, the polyalkylene glycoldi(meth)acrylate (B3) can be used. Specific examples thereof include apolyethylene glycol di(meth)acrylate having 2 to 14 ethylene groups, apolypropylene glycol di(meth)acrylate having 2 to 14 propylene groups,and a polybutylene glycol di(meth)acrylate having 2 to 14 butylenegroups, and from the viewpoint of sensitivity and the resistance toscumming, a diacrylate compound is preferable. From the viewpoint of theresolution and the adhesion, a polyethylene glycol dimethacrylate ispreferable. They can be used singly or in a combination of two or moretypes.

[0089] In this component (B3), the plurality of alkylene glycol chainsmay be identical to each other or different from each other. When two ormore types of alkylene glycol chains are present, the two or more typesof alkylene glycol chains may be present randomly or as blocks. Examplesof the above-mentioned compound having two or more types of alkoxygroups include a polyethylene/polypropylene glycol di(meth)acrylatehaving 2 to 14 ethylene groups and 2 to 14 propylene groups.

[0090] In another preferred embodiment, in order to further improve theresistance to scumming and the stripping properties, the compound (B4)having at least one ethylenically unsaturated bond and at least onephenyl or phenylene group per molecule can be used. The component (B4)is not particularly limited as long as it has at least one ethylenicallyunsaturated bond per molecule and at least one phenyl or phenylene groupper molecule, and examples thereof include compounds represented bygeneral formula (III) below:

[0091] (R denotes a hydrogen atom or a methyl group, X denotes analkylene group having 2 to 20 carbons, and s is an integer of 1 to 30),and a phthalic acid compound, and a compound represented by generalformula (III) above is preferable. The above-mentioned phenyl orphenylene group may have any substituent. X in general formula (III)above is preferably an ethylene group.

[0092] Examples of the substituent on the phenyl or phenylene groupinclude a halogen atom, an alkyl group having 1 to 20 carbons, acycloalkyl group having 3 to 10 carbons, an aryl group having 6 to 14carbons, an amino group, an alkylamino group having 1 to 10 carbons, adialkylamino group having 2 to 20 carbons, a nitro group, a cyano group,a mercapto group, an alkylmercapto group having 1 to 10 carbons, anallyl group, a hydroxyalkyl group having 1 to 20 carbons, a carboxyalkylgroup whose alkyl group has 1 to 10 carbons, an acyl group whose alkylgroup has 1 to 10 carbons, an alkoxy group having 1 to 20 carbons, and agroup containing a heterocycle. It is also possible for a hydrogen atomof the alkyl group to be replaced by a halogen atom. From the viewpointof the resistance to the developing solution, the developmentproperties, and the adhesion, an alkyl group having 1 to 20 carbons ispreferable, an alkyl group having 4 to 14 carbons is more preferable,and a nonyl group is particularly preferable. The number of substituentsis preferably 0 to 5, more preferably 1 to 4, particularly preferably 1to 3, and most preferably 1 or 2. When the number of substituents is twoor more, the two or more substituents may be identical to each other ordifferent from each other.

[0093] Examples of the compound represented by general formula (III)above include a nonylphenoxypolyethyleneoxy meth(acrylate), anonylphenoxypolypropyleneoxy (meth)acrylate, abutylphenoxypolyethyleneoxy (meth)acrylate, and abutylphenoxypolypropyleneoxy (meth)acrylate. From the viewpoint of theresistance to scumming, a nonylphenoxypolyethyleneoxy acrylate ispreferable. They can be used singly or in a combination of two or moretypes.

[0094] Examples of the nonylphenoxypolyethyleneoxy (meth)acrylateinclude nonylphenoxytetraethyleneoxy (meth)acrylate,nonylphenoxypentaethyleneoxy (meth)acrylate, nonylphenoxyhexaethyleneoxy(meth)acrylate, nonylphenoxyheptaethyleneoxy (meth)acrylate,nonylphenoxyoctaethyleneoxy (meth)acrylate, nonylphenoxynonaethyleneoxy(meth)acrylate, nonylphenoxydecaethyleneoxy (meth)acrylate,nonylphenoxyundecaethyleneoxy (meth)acrylate, andnonylphenoxydodecaethyleneoxy (meth)acrylate. Examples of availablecompounds include NP-8EA and NP-4EA (trade names, manufactured byKyoeisha Chemical Co., Ltd.) They can be used singly or in a combinationof two or more types.

[0095] With regard to the photopolymerization initiator (C), examplesthereof include benzophenone, N,N′-tetraalkyl-4,4′-diaminobenzophenonessuch as N,N′-tetramethyl-4,4′-diaminobenzophenone (Michler's ketone),aromatic ketones such as2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 and2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1, quinones suchas alkylanthraquinones, benzoin ether compounds such as benzoin alkylethers, benzoin compounds such as benzoin and alkylbenzoins, benzilderivatives such as benzil dimethyl ketal, 2,4,5-triarylimidazole dimerssuch as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, and2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, acridine derivativessuch as 9-phenylacridine and 1,7-bis(9,9′-acridinyl)heptane,N-phenylglycine, N-phenylglycine derivatives, and coumarin compounds.They can be used singly or in a combination of two or more types.Various properties of the photosensitive resin composition such as highsensitivity and low plating bath contamination depend on the type andthe amount of photopolymerization initiator used.

[0096] Among the above-mentioned components (C), in order to furtherimprove the sensitivity, the resolution, and the plating resistance and,in particular, from the viewpoint of the adhesion and the sensitivity,it is preferable to use a 2,4,5-triarylimidazole dimer. The substituentson the aryl groups of the two 2,4,5-triarylimidazoles may be identicalto each other so as to give a symmetric compound or may be differentfrom each other to give an asymmetric compound.

[0097] It is preferable to add anN,N′-tetraalkyl-4,4′-diaminobenzophenone such asN,N′-tetramethyl-4,4′-diaminobenzophenone (Michler's ketone), and fromthe viewpoint of increasing the curability at the bottom of the resistby increasing the light transmittance of the resist so as to adjust theabsorbance, the amount of N,N′-tetraalkyl-4,4′-diaminobenzophenone addedis preferably 0.04 to 0.08 parts by weight relative to the total ofcomponent (A) and component (B), more preferably 0.04 to 0.07 parts byweight, particularly preferably 0.045 to 0.06 parts by weight, and mostpreferably 0.045 to 0.05 parts by weight.

[0098] In another preferred embodiment, in order to improve the contrastand achieve a high aspect ratio by suppressing effectively unwantedgelling due to scattered light, etc., either or both of a compoundrepresented by general formula (I) above or a compound represented bygeneral formula (II) above can be used as component (D). From theviewpoint of the resolution, it is preferable to use a compoundrepresented by general formula (I). Use of the component (D) can furtherimprove the resolution and the plating resistance.

[0099] Each of the compounds represented by general formulae (I) and(II) above can have any substituent, and when there are a plurality ofsubstituents, the plurality of substituents may be identical to eachother or different from each other. The number of these substituents ispreferably 0 to 4, more preferably 0 to 3, particularly preferably 0 to2, very preferably 0 to 1, and most preferably 1.

[0100] Examples of the substituent include a halogen atom such asfluorine, chlorine, iodine, or astatine, an alkyl group having 1 to 20carbons, a cycloalkyl group having 3 to 10 carbons, an aryl group suchas a phenyl group or a naphthyl group, which may be substituted with anamino group or an alkyl group having 1 to 20 carbons, an amino group, amercapto group, an alkylmercapto group having 1 to 10 carbons, acarboxyalkyl group whose alkyl group has 1 to 10 carbons, an alkoxygroup having 1 to 20 carbons, and a group formed from a heterocycle, andit is preferable for the substituent to be an alkyl group.

[0101] Examples of the alkyl group having 1 to 20 carbons includemethyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl,pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, tridecyl,tetradecyl, pentadecyl, octadecyl, nonadecyl, icosyl, and structuralisomers thereof; it is preferable to use a butyl group such as n-butyl,sec-butyl, or tert-butyl, and it is more preferable to use tert-butyl.Examples of the above-mentioned cycloalkyl group having 3 to 10 carbonsinclude cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, andcyclooctyl. Examples of the aryl group substituted with an alkyl grouphaving 1 to 20 carbons include methylphenyl, ethylphenyl, andpropylphenyl.

[0102] Examples of the alkylmercapto group having 1 to 10 carbonsinclude methylmercapto, ethylmercapto, and propylmercapto. Examples ofthe carboxyalkyl group whose alkyl group has 1 to 10 carbons include acarboxymethyl group, a carboxyethyl group, a carboxypropyl group, and acarboxybutyl group. Examples of the alkoxy group having 1 to 20 carbonsinclude methoxy, ethoxy, and propoxy. Examples of the group formed froma heterocycle include an ethylene oxide group, a furan group, athiophene group, a pyrrole group, a thiazole group, an indole group, anda quinoline group.

[0103] In the above-mentioned general formula (I), m is an integer of 2to 6, preferably an integer of 2 to 4, more preferably an integer of 2to 3, and most preferably 2. When m is less than 2, the resolutiondeteriorates.

[0104] Examples of the compound represented by general formula (I)include catechol, resorcinol, 1,4-hydroquinone, alkylcatechols such as2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol,3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol,4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol,4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol,4-tert-butylcatechol, and 3,5-di-tert-butylcatechol, alkylresorcinolssuch as 2-methylresorcinol, 4-methylresorcinol, 2-ethylresorcinol,4-ethylresorcinol, 2-propylresorcinol, 4-propylresorcinol,2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, and4-tert-butylresorcinol, alkylhydroquinones such as methylhydroquinone,ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, and2,5-di-tert-butylhydroquinone, pyrogallol, and phloroglucinol; it ispreferable to use catechol, an alkylcatechol, an alkylhydroquinone, orhydroquinone, and among the alkylcatechols it is particularly preferableto use 4-tert-butylcatechol. They can be used singly or in a combinationof two or more types. Examples of the compound represented by generalformula (II) above include o-benzoquinone and p-benzoquinone.

[0105] In another preferred embodiment, the leuco dye (E) can be used asa hydrogen donor, and optimizing the amount of component (E) added canimprove the cure degree of the entire resist layer. Specific examples ofthe leuco dye include leuco crystal violet(tris(4-dimethylaminophenyl)methane),tris(4-diethylamino-2-methylphenyl)methane, leuco malachite green, leucoaniline, and leuco methyl violet, and from the viewpoint of a highhydrogen donating ability and the resolution not being degraded it ispreferable to use leuco crystal violet. The amount thereof added ispreferably 0.3 to 0.6 parts by weight relative to the total of component(A) and component (B), more preferably 0.3 to 0.5 parts by weight, andparticularly preferably 0.35 to 0.45 parts by weight.

[0106] In another preferred embodiment, in order to improve thecurability at the bottom of the resist by increasing the lighttransmittance of the resist so as to adjust the absorbance and achieveresolution and a high aspect ratio, it is possible to use aphotosensitive resin composition that can form a resist layer having anabsorbance of 0.50 or less at a wavelength of 365 nm, which is the mainactinic radiation output wavelength of an exposure unit used forexposure of an ordinary photosensitive film. As long as the absorbanceof the resist layer (photosensitive resin composition layer) is equal toor less than 0.50, the film thickness of the resist layer can be setfreely in a dry film thickness range of 1 to 100 μm.

[0107] Preferable amounts of each of the components to be added are nowexplained. The amount of component (A) added is preferably at least 40parts by weight relative to 100 parts by weight of the total ofcomponent (A) and component (B) from the viewpoint of the hardness(brittleness) of a light cured product and the coating properties whenused as a photosensitive element, preferably at most 80 parts by weightfrom the viewpoint of photosensitivity, and more preferably 45 to 70parts by weight.

[0108] The amount of component (B) added is preferably at least 20 partsby weight relative to 100 parts by weight of the total of component (A)and component (B) from the viewpoint of the photosensitivity, preferablyat most 60 parts by weight from the viewpoint of the hardness(brittleness) of the light cured product, and more preferably 30 to 55parts by weight.

[0109] The proportion of component (B1) in component (B) is preferablyat least 2 wt % from the viewpoint of the sensitivity and theresolution, preferably at most 40 wt % from the viewpoint of thestripping time, and more preferably 3 to 35 wt %. The proportion ofcomponent (B2) in component (B) is preferably at least 10 wt % from theviewpoint of the resolution, preferably at most 90 wt % from theviewpoint of the stripping time, and more preferably 20 to 80 wt %. Theproportion of component (B3) in component (B) is preferably at least 5wt % from the viewpoint of the sensitivity and the adhesion of finelines, preferably at most 60 wt % from the viewpoint of tackiness, andmore preferably 10 to 30 wt %. The proportion of component (B4) incomponent (B) is preferably at least 4 wt % from the viewpoint of thestripping time, preferably at most 20 wt % from the viewpoint of theadhesion of fine lines, and more preferably 6 to 12 wt %.

[0110] The amount of component (C) added is preferably at least 0.1parts by weight relative to 100 parts by weight of the total ofcomponent (A) and component (B) from the viewpoint of thephotosensitivity, preferably at most 10.0 parts by weight from theviewpoint of the curability of the bottom of the resist and thescumming, and more preferably 0.5 to 6.0 parts by weight.

[0111] The amount of component (D) added is preferably at least 0.001parts by weight relative to 100 parts by weight of the total ofcomponent (A) and component (B) from the viewpoint of the resolution,preferably at most 3 parts by weight from the viewpoint of thesensitivity, and more preferably 0.01 to 0.1 parts by weight.

[0112] Furthermore, the photosensitive resin composition can contain, asnecessary, a cationic polymerization initiator, a dye such as malachitegreen, a photo-coloring agent such as tribromophenylsulfone or leucocrystal violet, a thermal coloration inhibitor, a plasticizer such asp-toluenesulfonamide, a pigment, a filler, an anti-foaming agent, aflame retardant, a stabilizer, an adhesion imparting agent, a levelingagent, a stripping accelerator, an antioxidant, a perfume, an imagingagent, a thermal cross-linking agent, etc., the amount of each thereofbeing approximately 0.01 to 20 parts by weight relative to 100 parts byweight of the total of component (A) and component (B). They can be usedsingly or in a combination of two or more types.

[0113] The photosensitive resin composition used in the presentinvention can be dissolved, as necessary, in a solvent such as methanol,ethanol, acetone, methyl ethyl ketone, methyl Cellosolve, ethylCellosolve, toluene, N,N-dimethylformamide, or propylene glycolmonomethyl ether, or a mixed solvent thereof, and applied as a solutionhaving a solids content of about 30 to about 60 wt %. The use thereof isnot particularly limited, but it is preferably applied as a liquidresist on the surface of a metal such as copper, a copper alloy, iron,or an iron alloy, dried, and then used with a protective film laminatedthereto as necessary, or used in the form of a photosensitive element.

[0114] The photosensitive element according to the present invention,that is, a photosensitive element obtained by forming on a support aresist layer using the above- mentioned photosensitive resin compositionaccording to the present invention is now explained by reference todrawings.

[0115]FIG. 1 shows schematically one embodiment of the photosensitiveelement. A photosensitive element 1 includes a support 11 and a resistlayer (photosensitive resin composition layer) 12 formed thereon.

[0116] With regard to the support 11, a polymer film having heatresistance and solvent resistance, such as polyethylene terephthalate,polypropylene, polyethylene, or a polyester can be preferably used. Thethickness of the polymer film forming the support is preferably 1 to 100μm.

[0117] Although the method for forming the resist layer 12 on thesupport 11 is not particularly limited, it can be preferably obtained bycoating the support 11 with a solution of a photosensitive resincomposition and drying it. The coating thickness of the resist layerdepends on the use, but is preferably about 1 to about 100 μm as a drythickness, more preferably 3 to 80 μm, particularly preferably 5 to 50μm, very preferably 10 to 45 μm, and most preferably 20 to 40 μm. Thecoating can be carried out by a known method such as a roll coater, acomma coater, a gravure coater, an air knife coater, a die coater, or abar coater. The drying can be carried out at 70° C. to 150° C. for about5 to about 30 minutes. It is also preferable for the amount of organicsolvent remaining in the resist layer 12 to be 2 wt % or less from theviewpoint of preventing diffusion of the organic solvent in a subsequentstep.

[0118] The surface of the resist layer 12 of the photosensitive element1 is preferably covered with a protective film (not illustrated), whichis a polymer film such as polyethylene or polypropylene. It is alsopossible to laminate any one of the polymer films as a support andanother one of the polymer films as a protective film to oppositesurfaces of the resist layer. It is preferable to choose the protectivefilm so that the adhesive power between the resist layer and theprotective film is less than that between the resist layer and thesupport, and a film having a low level of fisheyes is preferable. Thethickness of the protective film is preferably at least 5 μm from theviewpoint of strength and at most 30 μm from the viewpoint of cost.

[0119] Since it should be possible to remove the support and theprotective film from the resist layer later, they should not besubjected to a surface treatment that makes it impossible to removethem, but they may be subjected to a surface treatment as necessary. Forexample, the support and the protective film may be subjected to anantistatic treatment as necessary.

[0120] The photosensitive element having a two or three layer structureincluding the support, the resist layer, and the protective film asnecessary may further include a middle layer or a protective layer suchas a cushion layer, an adhesive layer, a light absorbing layer, or a gasbarrier layer.

[0121] The photosensitive element thus obtained is stored in a roll formin which it is wound around a cylindrical core as it is or with afurther protective film laminated to the surface of the resist layer.When winding, it is preferable for the support to be on the outermostside. End face separators are preferably placed on end faces of thephotosensitive element roll thus wound from the viewpoint of protectionof the end faces, and moisture-resistant end face separators arepreferably placed from the viewpoint of resistance to edge fusion.Moreover, with regard to a packing method, it is preferable for it to bepackaged by wrapping with a black sheet having low moisturepermeability. As the core there can be cited, for example, a plasticsuch as a polyethylene resin, a polypropylene resin, a polystyreneresin, a polyvinyl chloride resin, and an ABS resin(acrylonitrile-butadiene-styrene copolymer).

[0122] A process for producing the resist pattern according to thepresent invention is now explained by reference to FIG. 2, which showsschematically one example of the steps thereof.

[0123] Firstly, in step (i) a resist layer is formed on a substrate 2(substrate for a circuit to be formed on), the resist layer being formedfrom any one of the above-mentioned photosensitive resin compositions ofthe present invention. Any method can be employed for forming the resistlayer and, for example, as shown in FIG. 2A, the above-mentionedphotosensitive element 1 is laminated to the substrate 2 so that theresist layer 12 is bonded to the surface of the substrate 2. Prior tothe lamination, in the case where a protective film (not illustrated) ispresent on the resist layer 12 of the photosensitive element 1, theprotective film is removed. An example of the lamination method is amethod in which the resist layer 12 is laminated to the substrate 2 bypressure-bonding with a pressure of about 0.1 to about 1 MPa (about 1 toabout 10 kgf/cm²) while heating the resist layer 12 at about 70° C. toabout 130° C. It is also possible to carry out the lamination underreduced pressure. The surface of the substrate 2 to be laminated isusually a metal surface, but it is not particularly limited thereto.Furthermore, heating the resist layer at 70° C. to 130° C. as describedabove can eliminate the need for preheating the substrate, but in orderto further improve the lamination performance, the substrate may bepreheated.

[0124] After formation of the resist layer is completed, in step (ii)the resist layer is imagewise exposed to actinic radiation so that anexposed area thereof is light cured. With regard to a method forimagewise exposure to actinic radiation, for example, as shown in FIG.2B, the resist layer 12 is imagewise exposed to actinic radiationthrough a negative or positive mask pattern 3, which is called artwork,thereby light curing an exposed area of the resist layer 12. With regardto a source of light for the actinic radiation, a known source of lightcan be used, examples thereof including those that are effective inradiating ultraviolet, visible light, etc. such as a carbon arc lamp, amercury-vapor arc lamp, a high pressure mercury lamp, and a xenon lamp.With regard to an exposure unit, a collimated light exposure unit ispreferable from the viewpoint of achieving resolution and a high aspectratio. Examples of the mask pattern include a PET mask pattern and aglass mask pattern, and from the viewpoint of preventing scattering anddiffraction and achieving resolution and a high aspect ratio the glasspattern is preferable. The exposure in step (ii) can be carried out in astate in which the support 11 is present, as long as the resist layer 12is not prevented from being exposed to radiation (in the case of atransparent support, etc.). It is also possible to carry out theexposure by direct laser imaging without having to use a mask pattern.

[0125] In the case where the support is present on the photosensitiveresin composition layer subsequent to the exposure, after removing thesupport, in step (iii) selectively removing an unexposed area of theresist layer by development can form a resist pattern 121 as shown inFIG. 2C. The development is carried out by wet development, drydevelopment, etc., and in the case of wet development a known methodsuch as a dip method, a spray method, brushing, or slapping is employedusing a developing solution corresponding to the composition of theresist layer, such as an alkaline aqueous solution, an aqueousdeveloping solution, or an organic solvent. It is also possible toemploy two or more types of development methods in combination asnecessary. Examples of the above-mentioned alkaline aqueous solutioninclude a 0.1 to 5 wt % diluted solution of sodium carbonate, a 0.1 to 5wt % diluted solution of potassium carbonate, and a 0.1 to 5 wt %diluted solution of sodium hydroxide. The pH of the alkaline aqueoussolution is preferably in the range of 9 to 11, and the temperaturethereof is adjusted in line with the developability of the resist layer.The alkaline aqueous solution may contain a surfactant, an antifoamingagent, an organic solvent, etc.

[0126] As a post development treatment, the resist pattern so formed canbe further cured by heating at about 60° C. to about 250° C. or bycarrying out irradiation at about 0.2 to about 10 J/cm² as necessary.

[0127] In order to form fine copper wiring with reduced electricalresistance and increased copper wiring density, in the case where thefilm thickness is 1 to 100 μm, the resist pattern of the presentinvention has an aspect ratio of 3.5 or higher, preferably 3.8 orhigher, more preferably 4.0 or higher, yet more preferably 4.3 orhigher, particularly preferably 4.5 or higher, very preferably 4.8 orhigher, and most preferably 5.0 or higher. The upper limit of the aspectratio is preferably about 10.0 from the viewpoint of ease of production,etc., more preferably 8.0, and particularly preferably 6.0. The aspectratio can be measured by, for example, an optical microscope or ascanning electron microscope (SEM). The ‘line width of the resistpattern’ when calculating the aspect ratio is preferably defined as theline width of the above-mentioned mask pattern for convenience ofmeasurement.

[0128] The film thickness of the resist pattern is preferably 1 to 100μm in order to further enhance the effects of the present invention,more preferably 3 to 80 μm, particularly preferably 5 to 50 μm, verypreferably 10 to 45 μm, and most preferably 20 to 40 μm.

[0129] A method for the formation of wiring using the resist pattern ofthe present invention is now explained. When carrying out wiringformation using the resist pattern of the present invention, the surfaceof the substrate is subjected to a known treatment such as etching,plating, etc. using the developed resist pattern as a mask.

[0130] Until now, the circuits of printed wiring boards have mainly beenformed by a subtractive process, that is, a technique involving forminga copper circuit by carrying out etching using a resist as a mask, butsince lateral etching (side etching) occurs as well as longitudinaletching, it tends to be disadvantageous for forming a fine wiringpattern. In order to reduce the influence of such side etching, makingthe copper layer thinner makes a certain level of fine pattern formationpossible, but it is anticipated that achieving a line/space (L/S) of 30μm or less would be very difficult. Because of these reasons, anadditive process can be considered as an effective technique for asemiconductor package substrate where formation of the finest copperwiring is required.

[0131] In the process for producing a semiconductor package substrate ofthe present invention, a circuit can also be produced more suitably bythe additive process involving plating rather than by the subtractiveprocess involving etching since the resist pattern of the presentinvention has an aspect ratio of 3.5 or higher when the film thicknessis 1 to 100 μm. The process for producing a semiconductor packagesubstrate according to the present invention therefore employs theadditive process, and explanation is made below by reference to FIGS. 3to 5, which show schematically one example of the steps thereof.

[0132] The additive process can be roughly divided into three processes,that is, a full additive process, a semi additive process, and a paneladditive process. The full additive process is, as shown in FIG. 3, aprocess for producing a semiconductor package substrate 5 in which aresist pattern 121 is formed on a substrate 2 (substrate for a circuitto be formed on), a plating 4 such as electroless plating issubsequently applied to gaps in the resist pattern, and the resistpattern 121 is then stripped to give a wiring pattern. The semi additiveprocess is, as shown in FIG. 4, a process for producing a semiconductorpackage substrate 5 in which a resist pattern 121 is formed on asubstrate 2 that has been subjected in advance to a plating 4 such aselectroless plating, the plating 4 such as electroplating issubsequently applied to gaps in the resist pattern, the resist pattern121 is then stripped, and the electroless plating applied in advance tothe substrate is finally subjected to quick etching using theelectroplated pattern as a mask to give a wiring pattern. The paneladditive process is, as shown in FIG. 5, a process for producing asemiconductor package substrate 5 in which a plating 4 such aselectroless plating required as wiring is applied to a substrate 2, aresist pattern 121 is formed thereon, etching is subsequently carriedout, and the resist pattern 121 is then stripped to give a wiringpattern. In the present invention, the semi additive process isparticularly effective.

[0133] Examples of the plating include copper plating, solder plating,nickel plating, and gold plating. Stripping of the resist pattern can becarried out using an aqueous solution that is more strongly alkalinethan the alkaline aqueous solution used for the development. As thestrongly alkaline aqueous solution, a 1 to 10 wt % aqueous solution ofsodium hydroxide, a 1 to 10 wt % aqueous solution of potassiumhydroxide, etc. can be used. Examples of the stripping method include animmersion method and a spray method.

[0134] In addition, when wiring is formed using the resist pattern ofthe present invention by the subtractive process involving etchinginstead of the above-mentioned additive process, the metal surface canbe etched using, for example, a cupric chloride solution, a ferricchloride solution, an alkaline etching solution, or a hydrogenperoxide-based etching solution.

[0135] Because the resist pattern of the present invention can provide ahigh wiring density, it is preferably used for the production of asemiconductor package substrate, but it can also be used for theproduction of a printed wiring board. The printed wiring board in thiscase may be a multilayer printed wiring board and may have smalldiameter through holes.

[0136] Since the resist pattern according to the present invention hashigh resolution and a high aspect ratio, use thereof enables a lowconductor resistance to be maintained in fine wiring, and it is usefulfor increasing the density of a semiconductor package substrate circuit.

[0137] The photosensitive resin composition and the photosensitiveelement according to the present invention are used as resist materialsfor pattern formation, can provide a resist pattern or a group of resistpatterns that have high resolution and a high aspect ratio and areuseful for increasing the density of a semiconductor package substratecircuit, and have excellent sensitivity, resolution, resistance toscumming, plating resistance, workability, and productivity.

[0138] In accordance with the process for producing a resist patternaccording to the present invention, a resist pattern having highresolution and a high aspect ratio can be produced with good workabilityand productivity. Use of the process enables a low conductor resistanceto be maintained in fine wiring, and is useful for increasing thedensity of a semiconductor package substrate circuit.

[0139] In accordance with the process for producing a semiconductorpackage substrate according to the present invention, since fine wiringin which a low conductor resistance is maintained can be carried outwith good workability and productivity using as a mask a resist patternhaving high resolution and a high aspect ratio, the process is usefulfor increasing the density of a semiconductor package substrate circuit.

[0140] The present invention is now explained further in detail byreference to experimental examples.

EXPERIMENTAL EXAMPLES 1 TO 7

[0141] A solution A was prepared by mixing the components shown in TABLE1.

[0142] In the solution A thus obtained were then dissolved thecomponents (B) and (D) shown in TABLE 2 to give a solution of aphotosensitive resin composition of each of the experimental examples.

[0143] The Compounds listed in TABLE 2 are shown below.

[0144] A-TMM-3 (trade name, manufactured by Shin-Nakamura Chemical Co.,Ltd.): tetramethylolmethane triacrylate represented by the formula below

[0145] TMPT21E (sample name, produced by Hitachi Chemical Co., Ltd.): anEO-modified trimethylolpropane trimethacrylate represented by theformula below

[0146] BPE500 (trade name, manufactured by Shin-Nakamura Chemical Co.,Ltd.): a compound represented by the formula below where p+q=10(2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane)

[0147] BP(EO)14MA: a compound represented by the formula above wherep+q=14 (2,2-bis(4-(methacryloxyheptaethoxy)phenyl)propane)

[0148] 4G (trade name, manufactured by Shin-Nakamura Chemical Co.,Ltd.): tetraethylene glycol dimethacrylate

[0149] 9G (trade name, manufactured by Shin-Nakamura Chemical Co.,Ltd.): nonaethylene glycol dimethacrylate

[0150] 9PG (trade name, manufactured by Shin-Nakamura Chemical Co.,Ltd.): nonapropylene glycol dimethacrylate

[0151] NP-4EA (trade name, manufactured by Kyoeisha Chemical Co., Ltd.):nonylphenoxytetraethyleneoxy acrylate represented by the formula below

[0152] NP-8EA (trade name, manufactured by Kyoeisha Chemical Co., Ltd.):nonylphenoxyoctaethyleneoxy acrylate represented by the formula below

[0153] Catechol: a compound represented by the formula below

[0154] 4-tert-Butylcatechol: a compound represented by the formula below

[0155] 2,5-Di-tert-butylhydroquinone: a compound represented by theformula below

[0156] 2,6-Di-tert-butyl-p-cresol: a compound represented by the formulabelow

[0157] A 16 μm thick polyethylene terephthalate film was then uniformlycoated with the solution of the photosensitive resin composition of eachof the experimental examples, and dried in a hot air convection dryer at100° C. for 10 minutes to give a photosensitive element. The filmthickness of the resist layer (photosensitive resin composition layer)thus obtained was 30 μm. The absorbance for ultraviolet radiation havinga wavelength of 365 nm of the resist layer thus obtained was measuredusing a UV spectrometer (a U-3410 spectrophotometer, manufactured byHitachi Ltd.) Firstly, the photosensitive element thus obtained wasplaced on the sample side, a support film was placed on the referenceside, the absorbance was measured continuously in the range of 700 to300 nm, and the value at 365 nm was read off. The absorbance forultraviolet radiation having a wavelength of 365 nm was 1.2 in all casesfor the resist layers of Experimental Examples 1 to 7.

[0158] A copper surface of a copper-clad laminate (MCL-E-61, trade name,manufactured by Hitachi Chemical Co., Ltd.), which is a glass epoxymaterial with copper foil (thickness 35 μm) laminated to oppositesurfaces thereof, was polished using a polishing machine (manufacturedby Sankei Co., Ltd.) having a #600 equivalent brush, water-washed, anddried under a flow of air, the copper-clad laminate thus treated washeated to 80° C., and the resist layer above of each of the experimentalexamples was laminated to the copper surface thereof while heating at110° C. to give a test piece.

[0159] <Sensitivity>

[0160] A Stouffer 41 step tablet was placed on the test piece as anegative, and the test piece was exposed at 60 mJ/cm², 120 mJ/cm², and240 mJ/cm² using an HMW 590 collimated light exposure unit having a highpressure mercury lamp (manufactured by ORC Manufacturing Co., Ltd.).After the exposure, the polyethylene terephthalate film was peeled off,and a 1 wt % aqueous solution of sodium carbonate was sprayed at 30° C.for 20 seconds so as to remove the unexposed portion.

[0161] The sensitivity of the photosensitive resin composition wasevaluated by measuring the number of steps of the step tablet of a lightcured film formed on the copper-clad laminate, and the sensitivity wasexpressed as an exposure (mJ/cm²) necessary to cure 15 steps of the 41step tablet (O.D.=0.05). The results thus obtained are given in TABLE 3.The lower the value, the higher the sensitivity.

[0162] <Resolution>

[0163] Each test piece was exposed at an exposure determined above usinga glass mask pattern as a negative and developed. The developed patternwas inspected and the resolution (μm) was obtained from a line width(μm) remaining as a line-and-space. In the evaluation of the resolution,the smaller the value the better.

[0164] <Aspect Ratio>

[0165] The aspect ratio was obtained from the film thickness (30 μm) ofthe resist layer and the line width (resolution) obtained above usingequation (2) above.

[0166] <Stripping Time>

[0167] A test piece that had been exposed at an exposure (15 steps/41)corresponding to its sensitivity was developed using a 1 wt % aqueoussolution of sodium carbonate. After allowing the test piece thusobtained to stand for one day, it was immersed in a 3 wt % aqueoussolution of sodium hydroxide maintained at 45° C. while stirring using astirrer, and the time (seconds) taken for stripping to start wasmeasured. A shorter stripping time is preferred.

[0168] <Scumming>

[0169] 0.5 m² of unexposed film of each test piece was dissolved in 1 Lof a 1 wt % aqueous solution of sodium carbonate, and the solution wascirculated in a spray developing machine at 30° C. for 90 minutes. Afterallowing it to stand for 2 minutes, an oily product attached to a wallof the developing machine was inspected, and the scumming was evaluatedusing the criteria shown below. The larger the number, the better theproperties.

[0170] 3: no oily product.

[0171] 2: a small amount of oily product.

[0172] 1: a large amount of oily product.

[0173] <Plating Resistance>

[0174] Each test piece was exposed using a mask at an exposure (15steps/41) corresponding to its sensitivity, and developed using a 1 wt %aqueous solution of sodium carbonate. These samples were degreased,water-washed, plated with copper sulfate at 3.0 A/dm² for 30 minutes,water-washed and immersed in fluoroboric acid, then solder-plated at 1.5A/dm² for 10 minutes, and water-washed. The moisture was removed by anair brush, cellophane tape (24 mm wide, manufactured by Sekisui ChemicalCo., Ltd.) was adhered to the sample and rapidly peeled off, and thepresence or absence of stripping was examined.

[0175] Good: no stripping.

[0176] Poor: stripping.

[0177] The results of the evaluation of each experimental example aregiven in TABLE 3. TABLE 1 Amount added/parts by weight ComponentSolution of copolymer of methacrylic Solids content 52 (A) acid/methylmethacrylate/styrene (ratio (solution 120) by weight 29/46/25)(weight-average molecular weight = 45,000) in methyl Cellosolve/toluene,solids content acid value = 189 mg KOH/g Component2,2′-Bis(2-chlorophenyl)-4,4′,5,5′- 3.0 (C) tetraphenylbisimidazole4,4′-Bis(diethylamino)benzophenone 0.3 Component Leuco crystal violet0.2 (E) Dye Malachite green 0.08 Solvent Acetone 10 Toluene 7N,N′-Dimethylformamide 3 Methanol 3

[0178] TABLE 2 Amount added/ Experimental Example parts by weight 1 2 34 5 6 7 Component A-TMM-3 10   — — — 10   10   — (B1) TMPT21E — 10  10   10   — — — Component 4G 10   10   10   — — — — (B2) 9G — — — 10  10   10   — 9PG — — — — — — 10   Component BPE-500 20   20   — — 20  20   20   (B3) BP (EO) 14MA — — 20   20   — — — Component NP-4EA  8   8   — —  8    8    8   (B4) NP-8EA — —  8    8   — — 18   ComponentCatechol  0.05 — —  0.05 — —  0.05 (D) 4-tert- —  0.05 — — — — —Butylcatechol 2,5-Di-tert-butyl — —  0.05 — — — — hydroquinone(Monohydric phenol compound) — — — — —  0.05 —2,6-Di-tert-butyl-p-cresol

[0179] TABLE 3 Experimental Example 1 2 3 4 5 6 7 Film thickness (μm) 3030 30 30 30 30 30 Sensitivity (mJ/cm²) 150 150 150 150 70 80 150Resolution (μm) 8.6 7 8.6 7 15 15 10 Aspect ratio 3.5 4.3 3.5 4.3 2.02.0 3.0 Stripping time (sec) 50 50 55 55 40 50 40 Scumming 3 3 3 3 3 3 3Plating resistance Good Good Good Good Good Good Good

EXPERIMENTAL EXAMPLES 8 TO 12

[0180] A solution B was prepared by mixing the components shown in TABLE4.

[0181] In the solution B thus obtained were then dissolved thecomponents (B) and (D) shown in TABLE 5 to give a solution of aphotosensitive resin composition of each of the experimental examples.

[0182] A compound listed in TABLE 5 is shown below.

[0183] SR454 (manufactured by Sartomer Company): an EO-modifiedtrimethylolpropane triacrylate represented by the formula below

[0184] A photosensitive element was obtained in the same manner as inExperimental Example 1, etc. except that the solution of thephotosensitive resin composition above was used, and the sensitivity,the resolution, the stripping time, the scumming, and the platingresistance of each test piece were evaluated in the same manner. Theresults of the evaluation are given in TABLE 6. The absorbance forultraviolet radiation having a wavelength of 365 nm was 0.38 in allcases for the resist layers of Experimental Examples 8 to 12. TABLE 4Amount added/parts by weight Component Solution of copolymer ofmethacrylic Solids content 58 (A) acid/methyl methacrylate/styrene/butyl(solution 130) methacrylate/ethyl acrylate (ratio by weight30/22/30/8/10) (weight-average molecular weight = 50,000) in methylCellosolve/toluene, solids content acid value = 194 mg KOH/g Component2,2′-Bis(2-chlorophenyl)-4,4′,5,5′- 3.2 (C) tetraphenylbisimidazole4,4′-Bis(diethylamino)benzophenone 0.05 Component Leuco crystal violet0.4 (E) Dye Malachite green 0.04 Solvent Acetone 10 Toluene 7N,N′-Dimethylformamide 3 Methanol 3

[0185] TABLE 5 Amount added/ Experimental Example parts by weight 8 9 1011 12 Component SR454  4    4    8   — — (B1) TMPT21E — — —  8    4  Component 4G —  6    6    6   — (B2) 9G  6   — — —  6   ComponentBPE-500 — 28   — 24   28   (B3) BP (EO) 14MA 28   — 24   — — ComponentNP-4EA  4    4    4    4    4   (B4) Component 4-tert-  0.04  0.04  0.04 0.04  0.04 (D) Butylcatechol

[0186] TABLE 6 Experimental Example 8 9 10 11 12 Film thickness (μm) 3030 30 30 30 Sensitivity (mJ/cm²) 190 190 190 190 190 Resolution (μm) 6.26.2 6.2 6.2 5.5 Aspect ratio 4.8 4.8 4.8 4.8 5.4 Stripping time (sec) 5050 50 55 50 Scumming 3 3 3 3 3 Plating resistance Good Good Good GoodGood

[0187]FIGS. 6A and 6B show SEM photographs of parts of the resistpatterns having an aspect ratio of 4.8 to 5.4 obtained in ExperimentalExamples 8 to 12 (the line width was 6.2 μm for 6A and 5.5 μm for 6B).As is clear from FIG. 6, resist patterns having high resolution and ahigh aspect ratio were obtained in which the resist pattern did notcollapse and there was no tailing in the rectangular cross sectionalprofile.

[0188] The above-mentioned experimental examples gave resist patternshaving a high aspect ratio of 3.5 or higher and having good propertiesin terms of the sensitivity, the resolution, the stripping time, thescumming, and the plating resistance. These high aspect ratio resistpatterns enable fine copper wiring to be formed and are excellent formaking a semiconductor package substrate. The copper wiring formedtherefrom had a sufficient cross section and a low electricalresistance.

[0189] The disclosure of the present application is related to thesubject matter of Japanese Patent Application No. 2000-293255 filed onSep. 27, 2000, Japanese Patent Application No. 2000-320168 filed on Oct.20, 2000, and Japanese Patent Application No. 2001-275523 filed on Sep.11, 2001, the disclosure of which is incorporated herein by reference.

[0190] It is to be noted that, besides those already mentioned above,various changes and modification can be made in the above-mentionedembodiments without departing from the novel and advantageous featuresof the present invention. Therefore, all such changes and modificationsare intended to be included within the scope of the appended claims.

1. A resist pattern having a film thickness of 1 to 100 μm and an aspectratio (ratio of the line width to the film thickness of the resistpattern) of 3.5 or higher.
 2. The resist pattern according to claim 1wherein the aspect ratio is 4.0 or higher.
 3. The resist patternaccording to claim 1 wherein the aspect ratio is 4.5 or higher.
 4. Theresist pattern according to any one of claims 1 to 3 wherein the filmthickness is 5 to 50 μm.
 5. The resist pattern according to any one ofclaims 1 to 3 wherein the film thickness is 20 to 40 μm.
 6. Aphotosensitive resin composition that can produce a resist patternhaving a film thickness of 1 to 100 μm and an aspect ratio (ratio of theline width to the film thickness of the resist pattern) of 3.5 orhigher.
 7. The photosensitive resin composition according to claim 6wherein it can produce a resist pattern having the aspect ratio of 4.0or higher.
 8. The photosensitive resin composition according to claim 6wherein it can produce a resist pattern having the aspect ratio of 4.5or higher.
 9. The photosensitive resin composition according to any oneof claims 6 to 8 wherein it can produce a resist pattern having the filmthickness of 5 to 50 μm.
 10. The photosensitive resin compositionaccording to any one of claims 6 to 8 wherein it can produce a resistpattern having the film thickness of 20 to 40 μm.
 11. The photosensitiveresin composition according to any one of claims 6 to 10, comprising aphotopolymerizable compound having three ethylenically unsaturated bondsper molecule.
 12. The photosensitive resin composition according to anyone of claims 6 to 11, comprising either or both of a compoundrepresented by general formula (I):

(in the formula, m is an integer of 2 to 6) or a compound represented bygeneral formula (II).


13. A photosensitive resin composition that can produce a group ofresist patterns in which a resist pattern having a film thickness of 1to 100 μm and an aspect ratio (ratio of the line width to the filmthickness of the resist pattern) of 3.5 or higher is adjacent, via aspace having the same width as the line width of the resist pattern, toa resist pattern having a film thickness of 1 to 100 μm and an aspectratio (ratio of the line width to the film thickness of the resistpattern) of 3.5 or higher.
 14. The photosensitive resin compositionaccording to claim 13 wherein the aspect ratio is 4.0 or higher.
 15. Thephotosensitive resin composition according to claim 13 wherein theaspect ratio is 4.5 or higher.
 16. The photosensitive resin compositionaccording to any one of claims 13 to 15 wherein the film thickness is 5to 50 μm.
 17. The photosensitive resin composition according to any oneof claims 13 to 15 wherein the film thickness is 20 to 40 μm.
 18. Thephotosensitive resin composition according to any one of claims 13 to17, comprising a photopolymerizable compound having three ethylenicallyunsaturated bonds per molecule.
 19. The photosensitive resin compositionaccording to any one of claims 13 to 18, comprising either or both of acompound represented by general formula (I):

(in the formula, m is an integer of 2 to 6) or a compound represented bygeneral formula (II).


20. A photosensitive resin composition comprising (A) a binder polymer,(B1) a photopolymerizable compound having three ethylenicallyunsaturated bonds per molecule, (C) a photopolymerization initiator, and(D) either or both of a compound represented by general formula (I):

(in the formula, m is an integer of 2 to 6) or a compound represented bygeneral formula (II).


21. A photosensitive resin composition comprising (A) a binder polymer,(B) a photopolymerizable compound having at least one ethylenicallyunsaturated bond per molecule, (C) a photopolymerization initiator, and(E) a leuco dye, the amount of component (E) added being 0.3 to 0.6parts by weight relative to 100 parts by weight of the total ofcomponent (A) and component (B).
 22. The photosensitive resincomposition according to claim 21 wherein the leuco dye (E) is leucocrystal violet.
 23. A photosensitive resin composition comprising (A) abinder polymer, (B) a photopolymerizable compound having at least oneethylenically unsaturated bond per molecule, and (C) aphotopolymerization initiator, the component (C) comprising anN,N′-tetraalkyl-4,4′-diaminobenzophenone at 0.04 to 0.08 parts by weightrelative to 100 parts by weight of the total of component (A) andcomponent (B).
 24. The photosensitive resin composition according to anyone of claims 21 to 23, comprising either or both of a compoundrepresented by general formula (I):

(in the formula, m is an integer of 2 to 6) or a compound represented bygeneral formula (II).


25. The photosensitive resin composition according to any one of claims21 to 24, comprising (B1) a photopolymerizable compound having threeethylenically unsaturated bonds per molecule as the component (B). 26.The photosensitive resin composition according to any one of claims 20to 25, further comprising (B2) a2,2-bis(4-((meth)acryloxypolyalkoxy)phenyl)propane.
 27. Thephotosensitive resin composition according to any one of claims 20 to26, further comprising (B3) a polyalkylene glycol di(meth)acrylate. 28.The photosensitive resin composition according to any one of claims 20to 27, further comprising (B4) a compound having at least oneethylenically unsaturated bond and at least one phenyl or phenylenegroup per molecule.
 29. The photosensitive resin composition accordingto any one of claims 20 to 28, comprising a 2,4,5-triarylimidazole dimeras the component (C).
 30. A photosensitive element obtained by formingon a support a resist layer formed from the photosensitive resincomposition according to any one of claims 6 to
 29. 31. A process forproducing a resist pattern having an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higher, theprocess comprising the following steps: i) a step of forming on asubstrate at a dry film thickness of 1 to 100 μm a resist layer formedfrom a photosensitive resin composition comprising a photopolymerizablecompound having three ethylenically unsaturated bonds per molecule; ii)a step of imagewise exposing the resist layer to actinic radiation sothat an exposed area thereof is light cured; and iii) a step ofselectively removing an unexposed area of the resist layer bydevelopment.
 32. A process for producing a resist pattern having anaspect ratio (ratio of the line width to the film thickness of theresist pattern) of 3.5 or higher, the process comprising the followingsteps: i) a step of forming on a substrate at a dry film thickness of 1to 100 μm a resist layer formed from a photosensitive resin compositioncomprising either or both of a compound represented by general formula(I):

(in the formula, m is an integer of 2 to 6) or a compound represented bygeneral formula (II);

ii) a step of imagewise exposing the resist layer to actinic radiationso that an exposed area thereof is light cured; and iii) a step ofselectively removing an unexposed area of the resist layer bydevelopment.
 33. A process for producing a resist pattern having anaspect ratio (ratio of the line width to the film thickness of theresist pattern) of 3.5 or higher, the process comprising the followingsteps: i) a step of forming on a substrate at a dry film thickness of 1to 100 μm a resist layer formed from a photosensitive resin compositioncomprising (A) a binder polymer, (B) a photopolymerizable compoundhaving at least one ethylenically unsaturated bond per molecule, (C) aphotopolymerization initiator, and (E) a leuco dye, the amount ofcomponent (E) added being 0.3 to 0.6 parts by weight relative to 100parts by weight of the total of component (A) and component (B); ii) astep of imagewise exposing the resist layer to actinic radiation so thatan exposed area thereof is light cured; and iii) a step of selectivelyremoving an unexposed area of the resist layer by development.
 34. Aprocess for producing a resist pattern having an aspect ratio (ratio ofthe line width to the film thickness of the resist pattern) of 3.5 orhigher, the process comprising the following steps: i) a step of formingon a substrate at a dry film thickness of 1 to 100 μm a resist layerformed from a photosensitive resin composition comprising (A) a binderpolymer, (B) a photopolymerizable compound having at least oneethylenically unsaturated bond per molecule, and (C) aphotopolymerization initiator, the component (C) comprising anN,N′-tetraalkyl-4,4′-diaminobenzophenone at 0.04 to 0.08 parts by weightrelative to 100 parts by weight of the total of component (A) andcomponent (B); ii) a step of imagewise exposing the resist layer toactinic radiation so that an exposed area thereof is light cured; andiii) a step of selectively removing an unexposed area of the resistlayer by development.
 35. A process for producing a resist patternhaving an aspect ratio (ratio of the line width to the film thickness ofthe resist pattern) of 3.5 or higher, the process comprising thefollowing steps: i) a step of forming on a substrate at a dry filmthickness of 1 to 100 μm a resist layer formed from a photosensitiveresin composition, the resist layer having an absorbance of 0.50 or lessat an actinic radiation wavelength of 365 nm; ii) a step of imagewiseexposing the resist layer to actinic radiation so that an exposed areathereof is light cured; and iii) a step of selectively removing anunexposed area of the resist layer by development.
 36. A process forproducing a resist pattern having an aspect ratio (ratio of the linewidth to the film thickness of the resist pattern) of 3.5 or higher, theprocess comprising the following steps: i) a step of forming on asubstrate at a dry film thickness of 1 to 100 μm a resist layer formedfrom a photosensitive resin composition; ii) a step of imagewiseexposing the resist layer to actinic radiation through a glass negativepattern so that an exposed area thereof is light cured; and iii) a stepof selectively removing an unexposed area of the resist layer bydevelopment.
 37. A process for producing a resist pattern having anaspect ratio (ratio of the line width to the film thickness of theresist pattern) of 3.5 or higher, the process including the followingsteps: i) a step of forming on a substrate at a dry film thickness of 1to 100 μm a resist layer formed from a photosensitive resin composition;ii) a step of imagewise exposing the resist layer to a collimated lightbeam so that an exposed area thereof is light cured; and iii) a step ofselectively removing an unexposed area of the resist layer bydevelopment.
 38. A process for producing a resist pattern having anaspect ratio (ratio of the line width to the film thickness of theresist pattern) of 3.5 or higher, the process including the followingsteps: i) a step of laminating to a substrate a photosensitive elementobtained by forming on a support a resist layer formed from thephotosensitive resin composition according to any one of claims 6 to 29in such a manner that the resist layer is bonded to a surface of thesubstrate; ii) a step of imagewise exposing the resist layer to actinicradiation so that an exposed area thereof is light cured; and iii) astep of selectively removing an unexposed area of the resist layer bydevelopment.
 39. A process for producing a semiconductor packagesubstrate wherein a circuit is formed by subjecting to an additiveprocess a substrate on which the resist pattern according to any one ofclaims 1 to 5 has been produced.
 40. A process for producing asemiconductor package substrate wherein a circuit is formed bysubjecting to an additive process a substrate on which a resist patternhas been produced by the process for producing a resist patternaccording to any one of claims 31 to 38.